Electric control for generators.



H. A. SCOTT.

ELECTRIC CONTROL FOR GENERATORS.

APPLICATION FILED ]AN.28,1916- Patented Aug. 20, 1918.

W ITNESS INVENTOR,

ATT'V.

HERBERT A. sco'rr, or snnrsnnns, PENNSYLVANIA.

ELEcra c oo vrnor. roa GENERATORS.

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Specification of Letters Patent.

Patented Aug. 26, 1918.

Application filed January 28, 1916. Serial No. 74,861.

To all whom it may concern:

Be it known that I, HERBERT A. Score, a citizen of the United States, residing at Saltsburg, in' the county of Indiana and State of Pennsylvania, have invented new and useful Improvements in Electric Controls for Generators, of which the following is a specification.

This invention relates to automatic control for elecric generators where the power supply is obtained from a plurality of sources of electrical generation.

As is well known the electrical requirements under cartain conditions are liable to be quite variable, betweentwo extremes, and as a result a power plant which is capable of taking care of the ordinary requirements may not be capable of responding to the abnormal conditions sometimes known as peakloads. The-peal:-loacls are usually taken care of by introducing storage batteries in the line or by utilizing some other auxiliary power which responds only when the demand on the line from the main plant eX- ceeds a predetermined limit.

It is the purpose of my invention to augment the supply of current to the main line by an auxiliary source of supply which will become effective only when the load reaches a predetermined limit, the auxiliary supply being cut out when the load drops back to the capacity of the generator in the main power plant.

The figure in the drawing illustrates a diagrammatic view of my invention.

Referring now to the drawing the nu meral 1 designates a main generator bridged across the mains 2 and 3. This main generator 1 is arranged at the main station and has placed in series therewith a circuit breaker t and a hand switch 5. Arranged in series in the main 2 is a solenoid 7 of a solenoid switch hereinafter known as the main switch. One end of the plunger of the solenoid terminates in a contact 8 with which cooperates a stationary contact 9. These contacts form the terminals for a break in a conductor 10, one terminal of which is connected to the main 3 and has its other terminal connected with an auxiliary generator 21 that is located at the substation and which is connected with the main 3.

As far as I have proceeded it will be seen that when the current in the mains 2 and 3 reaches a predetermined value, the solenoid 7 will raise the plunger and close the break in the conductor 10 with the result that a path is formed for the current from the generator 21.

Arranged in series with each other and the generator 21 in the conductor 10 is a solenoid 17 of an auxiliary switch 18; the coil 16 of an overload circuit breaker 15 and the coil 20 of a master cut in switch. The contacts 12 and 13 form the terminals for a second break in the conductor 10. These contacts are adapted to be bridged by the cross piece 1% of a circuit breaker 15' when the latter does not have the required tractive action. The movable arm 18 of the auxiliary switch is tapped onto the conductor 10 and cooperates with a contact 19 that is tapped onto the main 2. The master switch is of a solenoid type and has its core 22 pivotally connected to an arm 23 that is in turn connected to the main 3 by a conductor 26. This arm is electrically connected to a switch 24 that is adapted to engage the contact 25 that is in turn tapped onto the conductor 10.

' As soon as the current out-put of the generator 1 reaches a predetermined value the plunger of the solenoid 7 will be actuated for bringing the contacts 8 and 9 into engagement with each other and allow current to pass from the generator 21 through the coils 16, 17, and 20 back to the generator 21 by way of a portion of the main 3 and simultaneously with the actuation of the solenoid 7 the master cut in switch will be actuated and established a path for the current from the conductor 10 to the main 3 by way of the conductor 26, thus cutting a portion of the conductor 10 out of circuit.

The coil 17 throws the switch arm 18 into engagement with the contact 19 and bridges the generator 21 directly across the mains with the result that the coil 20 and the coil 16 receives the full current out put of the generator 21. It is of course to be understood that a certain amount of current is shunted through the coil 17 and back to the generator by the conductor 26.

Upon the current out put of the generator 21 decreasing a predetermined amount the master switch 20 will gravitate to open position and prevent the passage of current through the conductor 26. Previous to this action the contacts 8 and 9 are separated as the generator 1 has not been supplying the necessary amount of current owing to the fact that generator 21 in starting reduces the output of generator 1. As soon the master switch and contacts 8 and 9 open the solenoid 17 is relieved of current and as a result the arm 18 moves out of engagement with the contact 19 for cutting the generator 21 out of circuit.

Having described i ny invention what I claim is 1. In combination with a pair of mains, a main generator connected directly across the mains, an auxiliary generator, a switch responsive to. the current in the mains for forming a'complete circuit for the auxiliary generator and means arranged in said circuit adapted upon the completion of said circuit to connect the auxiliary generator di rectly across the mains.

2. In combination with a pair of mains, a main generator connected directly across the mains, an auxiliary generator, a switch responsive to the current in the mains for forming a complete circuit for the auxiliary generator, means arranged in said circuit adapted upon the completion of said circuit to connect the auxiliary generator directly across the mains, and means for completing the circuit. a

3. In combination with a pair of mains, a main generator bridged directly across the mains, an auxiliary generator, a main sole noid switch having'its coil arranged in one of the mains and adapted to close the auxiliary generator circuit, means for keeping said circuit closed and means energized upon the completion of the auxiliary generator circuit for connecting the auxiliary generator directly across the mains.

In testimony whereof I aflix my signature in presence of two witnesses.

HERBERT A. SCOTT. WVitnesses:

S. M. GRooKsHANK,

M. J. LYTLE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner, of Patents Washington, D. 0. i 

